The long term objectives of this project are to further understanding of the nature of and interaction between psychological and physical symptoms in patients with frequent panic attacks. Such understanding should help guide treatment strategies, provide improved measures of treatment outcome and provide information related to mind-body interactions important in both psychiatric and physical illnesses. The project aired include (1) identifying possible cardiovascular and/or psychological events which may trigger, accompany or follow panic attacks and (2) Characterizing cardiovascular and psychological reactivity during an ordinary day. Subjects will be patients with panic disorder or agoraphobia with panic attacks (n=50) recruited from our anxiety disorders clinic. Following a thorough psychiatric evaluation, baseline Heart Rate and Blood Pressure will be taken in a quiet room. Patients will then be equipped with ambulatory heart rate and blood pressure monitoring equipment for a period of 24 hours. During this time blood pressure will be automatically measured every 15 minutes. Patients will be asked to record their location, physical activity level, mental concentration level, mental concentration level and the occurrence of anxiety, unpleasant thoughts or environmental stress at the same 15 minute intervals. Heart rate will be recorded continuously. Descriptive analysis, a repeated measure ANOVA and a time series analysis will be used to characterize cardiovascular responses before, during and after spontaneous panic attacks. A fixed ANOVA will be used to compare daily blood pressure and heart rate patterns of panic patients to those of normal controls. Correlation coefficients will be used to study relationships between anxiety, unpleasant thoughts or environmental stress and heart rate and blood pressure.